Obviously--I'ld be watching this thread and now need to comment, particularly on time delay. My graduate work is in digital signal processing and using FFT filters in the digital domain with narrow band parametrics leaves digital artifacts--there's no way around this. When you try to correct for time coherencies depending on the frequency and the correction these same "ringing" type of artifacts occur. This is one reason we designed a parametric in the analog domain.
We designed the PARC to solve bass problems for existing rooms which there was no other realistic solution for. There are always passive solutions--but implementing some of them can be very expensive, time consuming, and basically just not worth it. The PARC had to perform for very high end systems, which we felt there was no system on the market that had the signal transparency required for high end. The PARC is limited to low frequencies. It only operates below 350 Hz, and we recommend that it only be used below 200 Hz. Keep in mind middle C on the piano is 260 Hz--most people know that the frequency spectrum is logrythmic, but not so many know how quickly you reach middle C. Everything above 350 Hz is band passed, so it can remain pure. Our philosophy remains--no electrical correction is the best--unless you have a bass problem that can not be taken care of otherwise. If this is the case, then do it in the analog domain. Why? First, there's no additional or limitations in with any D/A or A/D conversion. This will yield the best transaparency, particularly when the mid/high fequencies are band passed. Second, the phase shift in a low frequency of a minimum phase system (your room) is the inverse of an analog parametric filter. What this means is that a parametric filter in the analog domain automatically corrects for the time/phase shift that was originally caused by the room mode. This is something that is inherent to the system--where nature actually works for us. The whole principle is very simple.
If you read the Absolute Sound Review, Robert Greene is the review and a professor of mathmatics at Stanford. He mentions the phase issues in a very eliquent way.
There is no question the TACT has many more features than the PARC, but of those we've found none that are useful if you deal with the room (even in very mild terms). Only the bass remains a significant problem where 4 feet of traps or custom designed Helmhotz resonators are out of the question for either cost or aesthetic reasons. In these cases, the PARC will yield the most transparent method of dealing with this one very common and problematic issue.
We designed the PARC to solve bass problems for existing rooms which there was no other realistic solution for. There are always passive solutions--but implementing some of them can be very expensive, time consuming, and basically just not worth it. The PARC had to perform for very high end systems, which we felt there was no system on the market that had the signal transparency required for high end. The PARC is limited to low frequencies. It only operates below 350 Hz, and we recommend that it only be used below 200 Hz. Keep in mind middle C on the piano is 260 Hz--most people know that the frequency spectrum is logrythmic, but not so many know how quickly you reach middle C. Everything above 350 Hz is band passed, so it can remain pure. Our philosophy remains--no electrical correction is the best--unless you have a bass problem that can not be taken care of otherwise. If this is the case, then do it in the analog domain. Why? First, there's no additional or limitations in with any D/A or A/D conversion. This will yield the best transaparency, particularly when the mid/high fequencies are band passed. Second, the phase shift in a low frequency of a minimum phase system (your room) is the inverse of an analog parametric filter. What this means is that a parametric filter in the analog domain automatically corrects for the time/phase shift that was originally caused by the room mode. This is something that is inherent to the system--where nature actually works for us. The whole principle is very simple.
If you read the Absolute Sound Review, Robert Greene is the review and a professor of mathmatics at Stanford. He mentions the phase issues in a very eliquent way.
There is no question the TACT has many more features than the PARC, but of those we've found none that are useful if you deal with the room (even in very mild terms). Only the bass remains a significant problem where 4 feet of traps or custom designed Helmhotz resonators are out of the question for either cost or aesthetic reasons. In these cases, the PARC will yield the most transparent method of dealing with this one very common and problematic issue.